Transfer copy process and material

ABSTRACT

An upper sheet and a lower sheet are provided, adapted to be superimposed to form an interface between said sheets, and are coated on said interface with all ingredients required for a heat-induced, color-producing chemical reaction. The upper sheet has on a side adapted to form said interface a coating which contains at least one of said ingredients and which is locally transferable to said lower sheet under the action of writing pressure applied to said upper sheet. When the two sheets are superimposed to form said interface, writing pressure is applied to said upper sheet to transfer parts of said coating to said lower sheet, which is subsequently heated to induce said colorproducing chemical reaction.

ilriited tates Ptent Schutzner 51 Feb.8,1972

[54] TRANSFER COPY PROCESS AND MATERIAL [72] Inventor: Walter Schutzner, Vienna, Austria [73] Assignee: W. Koreska, Vienna, Austria [22] Filed: Oct. 17, 1968 21 Appl. No.: 768,346

FOREIGN PATENTS 0R APPLICATIONS 835,930 5/1960 Great Britain ..117/362 852,131 10/1960 Great Britain ..117/36.2

Primary Examiner-Murray Katz Att0rney-Karl F. Ross [57] ABSTRACT An upper sheet and a lower sheet are provided, adapted to be superimposed to form an interface between said sheets, and are coated on said interface with all ingredients required for a heat-induced, color-producing chemical reaction. The upper sheet has on a side adapted to form said interface a coating which contains at least one of said ingredients and which is 10- cally transferable to said lower sheet under the action of writing pressure applied to said upper sheet. When the two sheets are superimposed to form said interface, writing pressure is applied to said upper sheet to transfer parts of said coating to said lower sheet, which is subsequently heated to induce said color-producing chemical reaction.

2 Claims, 3 Drawing Figures I PAIENTEurca a 1912 FIG! 53 mmumuuam 62 'I'IIIIA O i 73 'IIIIIIL Walfer Schufzner *nvenfor.

TRANSFER COPY PROCESS AND MATERHAL This invention relates to a process of making multiple records with the aid of color-producing chemical reactions. More particularly, the invention is concerned with a novel transfer copy system.

Various processes of making multiple records without interleaved carbon paper have already been proposed. One class of such processes are based on the transfer of carbon. The sheet which is written upon is provided on the rear with a coating, which produces marks on an underlying sheet of paper under the action of writing pressure.

Such carbon layers render the handling of the papers more difficult and tend to soil the hands and the backing surface. It is also difiicult to avoid the making of undesired copies. In view of these disadvantages of carbon-coated papers, colortransferring coating have been designed, which enable a transfer under pressure in cooperation with special receiving layers only, which in most cases contain wax.

in the latter arrangement, the danger of undesired copies was reduced but not entirely eliminated. With increasing use of this copying process in a typing office, there will arise an increasing probability of a color-transferring layer and a receiving layer to become superimposed so that undesired copies can be made.

Another class of processes are based on color-producing chemical reactions.

In the latter processes, the production of undesired copies is avoided in that each sheet is provided on its rear with an inherently colorless substance giving a color-producing chemical reaction upon contact with a second colorless substance selected to match the first substance. The second substance is provided as a coating on the face of the succeeding sheet.

Under the writing pressure, part of the first substance is transferred to the copy sheet, where it contacts the second substance so that the reaction takes place immediately.

The use of this system enables also an undesired making of copies if two corresponding sheets for use in the same transfer copy process become incidentally superimposed in the filing tray. Besides, such sets of writing papers do not have a long shelf life because the color-producing reaction may be caused under the pressure due to the weight of the paper itself.

It is an object of the invention completely to prevent formation of undesired copies.

The process according to the invention is mainly characterized in that at least one of the ingredients required for the reaction is transferred under the action of the writing pressure to a copy sheet, where it is contacted with any other ingredients which may be required for such reaction, and the reaction is subsequently effected by heating.

in one embodiment of the invention, a copying material is utilized consisting of at least two superimposed sheets. At least one of the ingredients required for the color-producing reaction is contained in a coating provided on the underside of the upper sheet and adapted to be transferred by local pressure onto the underlying sheet. That coating preferably contains a film-forming binder, desirably having a loosened, particulate structure. Such structure may be obtained, e.g., by an incorporation of waxes or waxlike substances.

In a particularly preferred embodiment of the invention, the lower sheet is provided on its upper face with a receiving coating containing a waxlike binder and, if required, one or more of the other ingredients required for the reaction.

Alternatively, all ingredients required for the color-producing reaction may be incorporated in the transferable coating. in this case, it is sufficient to provide a receiving coating which contains a waxlike binder only, which upon a temperature rise acts as a solvent for at least one of the two ingredients.

It is also possible to provide a cover layer over the transferable coating, the cover layer consisting preferably of waxlike substances, similar to the receiving coating previously mentioned, and which causes the particles detaching from the transferable coating under the action of the writing pressure to adhere to ordinary paper.

The waxlike substances in the covering or in the receiving coating are preferably selected to melt at a temperature in the range of 60150 C.

In a special embodiment of the invention, the waxlike substance may be one of the reactants, e.g., a heavy metal soap.

It is apparent from the above that the formation of undesired copies may be prevented not only by choice of the ingredients required for the reaction similar to the known process outlined above, but also by the fact that the writing remains invisible unless the copy sheet is heat treated. Such heat treatment will hardly be applied to filed letters so that a formation of undesired copies can be entirely prevented.

When two or more sheets according to the invention are superimposed in a copying set, the uppermost sheet should have a coating on the underside only and the lowermost sheet on the upper side only whereas the intermediate sheets are provided with coatings on both sides.

The invention will be described more fully hereinafter with reference to some examples:

EXAMPLE 1 The following ingredients were jointly ground in a ball mill: 5 parts by weight Vinylite VYHl-Ll (a polyvinylchlorideacetate copolymer) 45 parts by weight kaolin 30 parts by weight methyl gallate 200 parts by weight acetone.

The resulting mix was applied to writing paper as a coating having a dry weight of 5-6 grams per. square meter. This coating forms the rear side of the sheet.

The sheet is provided on its forward face with a receiving coating having the following composition:

10 parts by weight ozokerite 2 parts by weight ferric stearate.

The mixture is fused and applied to the paper as a coating having a weight of 2-3 grams per square meter.

When two papers thus coated are superimposed in such a manner that the rear side of the first-mentioned sheet lies adjacent to the forward side of the second sheet, the application of pressure, e.g., by the impact of a type or by a pencil or ball point pen, will cause parts of the transferable coating to be transferred to the receiving coating where the transferred matter remains invisible initially. If the copy sheet is subjected to a heat treatment e.g., in a drying cabinet adjusted to a temperature of 1 10 C., a black writing will be produced. Instead of being heated in a drying cabinet, the sheet may be heated by means of a heated roll, a hotplate or a flatiron. Altematively, the writing may be developed by infrared radiation or by a hot air stream. It is essential, however, that the heating is sufficient to melt at least one ingredient, in the present case the mixture of ozokerite and ferric stearate, so that the reaction with the methyl gallate is initiated at those portions which correspond to the writing.

EXAMPLE 2 The rear side of a writing paper is provided similarly with a coating having the following composition: 5 parts by weight Vinylite VYHH-l 10 parts by weight cetyl alcohol 50 parts by weight kaolin 25 parts by weight dimethylglyoxime 200 parts by weight acetone.

The coating has a dry weight of 5-6 grams per square meter. The receiving coating consists of a mixture of 10 parts by weight ozokerite 2 parts by weight nickel stearate A red writing is formed.

EXAMPLE 3 A transferable coating is produced using the following composition: 5 parts by weight Vinylite VYHH-l 50 parts by weight kaolin 10 parts by weight dithioxamide 150 parts by weight acetone.

The receiving coating may consist of the same mixture as in Example 2.

A black writing is formed.

- EXAMPLE 4 The transferable coating is applied using the following mixture: 5 parts by weight ethyl cellulose I 50 parts by weight kaolin parts by weight potassium rhodanide 200 parts by weight denatured alcohol.

The receiving coating consists of the following mixture: 8 parts by weight microcrystalline wax 2 parts by weight polyethylene 2,000-5,000 2 parts by weight cobalt stearate.

A blue writing is obtained.

(molecular weight EXAMPLE 5 Potassium rhodanide mentioned in Example 4 is replaced by 10 parts malachite green-lactone. The receiving coating consists of 10 parts by weight ceresine I part by weight n-dodecylgallate.

A green writing is obtained.

EXAMPLE 6 The malachite green-lactone mentioned in Example 5 is replaced by the same amount of N-phenyl leukoauramine. The receiving coating has the composition described in Example 5. A blue writing is obtained.

EXAMPLE 7 The transferable coating is made from 60 parts by weight ozokerite 30 parts by weight petroleum jelly 10 parts by weight dodecylgallate.

The ingredients are fused together. The melt is applied to form a coating having a weight of 5-6 grams per square meter. The forward side of the sheet is provided with a receiving coating as stated in Example 1. A black writing is obtained just as in Example 1.

EXAMPLE 8 EXAMPLE 9 Instead of providing a receiving coating on a separate sheet, as described in the foregoing examples, the transferable coating on the rear side of the sheet may be covered with a dispersion of polyethylene (molecular weight 4,000-6,000) in gasoline, Paraffin may be added to the dispersion, if desired.

Writing pressure applied to such writing sheet will cause a transfer of the reactive substances to any desired paper surface, which may be uncoated. Undesired copies will not be formed unless the sheet is subsequently heated.

EXAMPLE 10 If the zinc dibutyldithiocarbamate mentioned in Example 8 is replaced by about 12 grams mercury monobenzyldithiocarbamate, a black writing will form on the copy sheet after a heat treatment. In this case it will be suitable to replace the ferric stearate by the same amount ofa wax which does not participate in the reaction, such as cetyl alcohol. That wax loosens the structure of the binder or of the entire coating so as to ensure an adequate transfer of the transferable coating to the receiving coating.

The above-mentioned mercury monobenzyldithioearba mate may be replaced by other colorless or brightly colored salts of derivatives of dithiocarbamic acid, such as are mentioned in the US. Pat. No. 2,999.035.

In addition to the reactions mentioned in the above examples, numerous other color-producing chemical reactions may be used in the transfer copy process according to the invention.

For instance, reactants for monomolecular color-producing reactions will mainly be used in transferable coatings to be transferred to any desired paper, which may be uncoated. Bimolecular reactions are particularly suitable in transfer copy systems because they afford an absolute safety against formation of undesired copies and enable to produce writings in different colors by selection of suitable reactants. For instance, different areas of the copy sheet may be provided with receiving coatings having different compositions selected so that writings in different colors will be produced as a result of the cooperation of such receiving coatings with one and the same transferable coating on a subsequent heat treatment. A]- ternatively, a uniform receiving coating may be combined with transferable coatings containing different reactants selected to give writings in different colors on one and the same copy sheet.

The invention by no means is restricted to monoor bimolecular reactions because more complex reaction mechanisms may be used as well. For instance, one of the two cooperating coatings, e.g., the receiving coating, may contain a catalyst, which will initiate a reaction between two reactants upon heating only. In this case it makes no difference whether the two reactants are both contained in the transferable coating or one reactant is contained in the transferable coating and the other is the receiving coating.

The invention will be further explained with reference to the drawing, which shows in FIGS. 1 to 3 three different embodiments of parts of sets of copying sheets in greatly exaggerated thickness in fragmentary vertical sectional views.

FIG. 1 shows a top sheet 10,an intermediate sheet 20 and a bottom sheet 30. It will be apparent that the top sheet 10 and the bottom sheet 30 are upper and lower sheets, respectively, with respect to the intermediate sheet 20, and that the latter is a lower sheet with respect to the top sheet 10 and an upper sheet with respect to the bottom sheet 30.

The top sheet 10 has a backing layer 11 of paper and a transferable coating 12 facing the intermediate sheet 20. The intermediate sheet 20 has a core layer 21 of paper, a receiving coating 22 facing the coating 12 and a transferable coating 23 facing the bottom sheet 30. The bottom sheet 30 has a backing layer 31 of paper and a receiving coating 32 facing the transferable coating 23.

The transferable coatings 12 and 23 and the receiving coatings 22 and 32 may be composed as described for such coatings in Examples 1 to 7.

FIG. 2 shows a top sheet 40, an intermediate sheet 50, and a bottom sheet 60. It will be apparent that the top sheet 40 and the bottom sheet 60 are upper and lower sheets, respectively, with respect to the intermediate sheet 50, and that the latter is a lower sheet with respect to the top sheet 40 and an upper sheet with respect to the bottom sheet 30.

The top sheet 40 has a backing layer 41 of paper and a transferable coating 42 facing the intennediate sheet 40. The

intermediate sheet 50 has a core layer 51 of paper, a receiving coating 52 facing the coating 42 and a transferable coating 53 facing the bottom sheet 60. The bottom sheet 60 has a core layer 61 of paper and a receiving coating 62 facing the coating 53.

The transferable coatings 42 and 53 and the receiving coatings 52. and 62 may be composed as described for such coatings in Examples 8 and 10.

FIG. 3 shows an upper sheet 70 and a lower sheet 80. The upper sheet 70 has a backing layer 71 of paper and a transferable coating 72, which is covered by a coating 73 of wax or waxlike material, e.g., as described in Example 9. The lower sheet 80 consists on its surface facing the coating 73 of a material to which the material of the coating 73 can adhere. The transferable coating 72 may be composed as described for such coating in Examples 8 and 10.

What is claimed is:

1. A method of producing a copy, comprising the steps of:

preparing a stack of sheets of a flexible substrate, each coated on one surface with a transferable layer consisting essentially of a polymeric binder, a pigmentatious or filler substance and a heater-activatable colorant for producing a visible image upon solubilization in molten wax and substantially nontransferable under pressure to nonwaxy bases, and coated on its opposite surface with a receiving layer of a wax preferentially accepting said colorant to produce a latent image, said stack having the transfer layer of one sheet in contact with the receiving layer of an adjoining sheet; applying local pressure to said stack to effect a localized transfer of the colorant from one sheet to the receiving layer of the adjoining sheet and forming a substantially invisible trace therein; and heating the receiving layer of said adjoining sheet substantially to the melting point of said wax, thereby rendering visible the trace formed in the receiving layer by the transferred colorant, the transferable layer consisting essentially of 5 parts by weight of a polyvinyl chloride-vinyl acetate copolymer, 45 parts by weight of kaolin, 20 parts by weight of ferric stearate and 10 parts by weight of zinc dibutyldithiocarbamate, said receiving layer consisting of ozocerite wax.

2. A multiple copy paper comprising a flexible substrate having a pair of opposite surfaces; a first layer coated onto one of said surfaces and consisting of a composition transferable under pressure substantially only to a waxy coating and composed essentially of a synthetic resin binder, pigmentatious or filler material imparting coloration to said layer, and at least one thermally activatable color precursor producing a visible trace upon heating in melted wax; and a waxy receiving layer on the other surface preferentially receiving a transfer of said color precursor upon the application of local pressure to a similar sheet and confronting same with its color-precursorcontaining layer to produce a substantially invisible latent image of the trace produced by such local pressure whereby the trace is rendered visible upon heating of the receiving layer, the first layer consisting essentially of 5 parts by weight of a polyvinyl chloride-vinyl acetate copolymer, 45 parts by weight of kaolin, 20 parts by weight of ferric stearate and 10 parts by weight of zinc dibutyldithiocarbarnate, said receiving layer consisting of ozocerite wax.

" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,640,750 Dated 14'A ri1 1972 Inventor(s) Walter SCHUTZNER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the Patent under Point 30,

read AUSTRIA for "AUSTRALIA" Signed and sealed this 11th day ofJUly .1972.

(SEAL Attest:

EDI JARD M.FLETCHER,JR. ROBERT GOTI'SCHALK Attesting Officer Commissioner of Patents 

2. A multiple copy paper comprising a flexible substrate having a pair of opposite surfaces; a first layer coated onto one of said surfaces and consisting of a composition transferable under pressure substantially only to a waxy coating and composed essentially of a synthetic resin binder, pigmentatious or filler material imparting coloration to said layer, and at least one thermally activatable color precursor producing a visible trace upon heating in melted wax; and a waxy receiving layer on the other surface preferentially receiving a transfer of said color precursor upon the application of local pressure to a similar sheet and confronting same with its color-precursor-containing layer to produce a substantially invisible latent image of the trace produced by such local pressure whereby the trace is rendered visible upon heating of the receiving layer, the first layer consisting essentially of 5 parts by weight of a polyvinyl chloride-vinyl acetate copolymer, 45 parts by weight of kaolin, 20 parts by weight of ferric stearate and 10 parts by weight of zinc dibutyldithiocarbamate, said receiving layer consisting of ozocerite wax. 